'92 not shifting into O.D. and no speedometer!

[Beach]

92 w-250 4x4. The truck is not shifting into overdrive and the speedometer does not work! Have checked the throttle position sensor voltage which is . 5 volt's at idle and 2. 5-3 at wide open. Replaced the speed sensor on the transfercase and still no O. D. or speedo! Any suggestion's, thank's! Oo.

 

[Philip]

Check that little gear reducer box to see if it is turning the speed sensor.

 

[Beach]

Hey Philip, thank's for the suggestion. This truck belong's to a buddy and he checked the gear reducer box, he found a broken, seized gear?! So it look's like that was the problem. Thank's again!

 

[BushWakr - RIP]

Boy, I sure wish my speedo fix was that easy..... blasted thing say's I'm doing like 175 MPH while I'm still in the driveway..... course the up side is when I get pulled over and the officer asks if I know how fast I was going I can honestly say..... "NOPE" or "YUP, according to my speedo, I was doing 175 MPH"..... hmmmm, I wonder if they'll have a sense of humor on this one... .



pb...

 

[mysteryman]

speedometer troubles

Take the speed sensor off of the adapter and drive it with a cordless drill in both directions and see if the speedo reads anything..... If it does check the gears in the right angle adapter... . If they are good pull the drive pinion out of the trans and see if it is melted or has broken teeth..... If they are good check to see if the nut that holds the yoke onto the main shaft is tight... . If it is loose the worm gear will just spin on the main shaft... .



What often happens to getrags is the rear main shaft bearing goes bad causing the main shaft to go off center and wipe out the worm and pinion gears for the speedo... . When the speedo stops working due to melted gears from a worn rear bearing . It will not be long till the trans breaks some drive gears...



Keep in mind that I am speaking of a 2wd truck... If you have a 4wd the speedo drive is in the transfer case... the same principles apply... .



We did have a lot of troubles with rear output bearing failures . Even in the gas trucks... .



For those of you that have erratic speedo's or a jumping needle. There are 2 basic reasons this happens assuming that the wiring is in good condition...



The sensor on the trans will develop rust particles inside it's casing that stick to the magnet... . To save it peel back the crimp collar and clean it out... Most of the time it will fix it...



The second is the electrolytic capacitors on the circuit board on the speedo head... They are kind of like tiny batteries..... The have fluid in them. It dries out in time causing them to loose capacity... Capacitors are rated in what we call microfarads, ("uf" or an upside down U for short)... . The caps are marked. I have a tester to test them with but the caps are so cheap just replace them all and don't worry about testing them... Replace them with caps that match the old ones... You should be able to find them at radio shack..... Good luck